The 26-year-old who was taken on a wild ride with the two brothers suspected of the Boston Marathon bombings told investigators he found a way to escape when the brothers stopped for gas, and then called police. On Friday, surviving Boston Marathon bombing suspect Dzhokhar Tsarnaev was moved to a medical prison, still unable to speak but declared alert and mentally competent. NBC's Michael Isikoff reports.

By Michael Isikoff and Jonathan Dienst, NBC News

The investigation into the Boston Marathon bombings has expanded to a landfill 60 miles south, where authorities are searching for a missing laptop computer and other clues.

Law enforcement sources tell NBC News that investigators on Friday scoured the landfill in New Bedford, Mass., for items that might belong to bombing suspect Dzhokhar Tsarnaev, including the laptop and receipts related to the purchase of fireworks.

New Bedford is just eight miles from the campus of University of Massachusetts-Dartmouth, where Tsarnaev was a student.

Tsarnaev, 19, was transferred early Friday from a Boston hospital to the federal prison at Fort Devens, Mass. He and his brother Tamerlan Tsarnaev, 26, are suspected of detonating two bombs seconds apart near the finish line of the Boston Marathon on April 15, killing three people and injuring more than 260 more.

Police say the brothers fatally shot a Massachusetts Institute of Technology campus police officer in Cambridge three days later before carjacking an SUV and then engaging in a shootout with police in nearby Watertown. Tamerlan Tsarnaev was killed in the confrontation. Dzhokhar Tsarnaev was later taken into custody after a citywide manhunt.

Police say the brothers set off a number of bombs during the chase and shootout in the early hours of April 19 in Watertown, Mass., after the Tsarnaev’s carjacked the SUV and briefly held its driver hostage.

Details of that carjacking emerged Friday. The victim – a 26-year-old Chinese immigrant who has asked to be identified only as “Danny” – recounted the harrowing 90 minutes he was a hostage to James Alan Fox, a Northeastern University professor. Fox said that Danny was scared for his life but made small talk and played up his foreign heritage to the brothers.

Veterans from the Semper Fi Fund, a nonprofit that provides financial support to injured soldiers, visited survivors of the Boston bombings, providing hope and support. NBC's Katy Tur reports.

Danny said the Tsarnaevs told him they were responsible for the marathon bombings. He said the brothers openly discussed going to New York – where authorities have said an attack on Times Square was discussed.

When the brothers stopped for gas, Danny bolted, then called police, who tracked the stolen Mercedes using GPS and Danny’s abandoned cell phone.

“He was only trying to save himself,” Fox told NBC News. “But through that process, it looks like he may have saved countless others.”

In New York, Police Commissioner Ray Kelly told reporters Friday that he had “expressed concern” to the FBI about what he said was a 48-hour lag in information about the intended New York trip. The FBI had initially told NYPD that the bombing suspects planned to come to New York to party after the bombing, but then said the brothers had decided to set off their remaining pipe bomb and pressure cooker explosives in Times Square.

Kelly said he did not know why there had been a lag in the communication. “We think it’s important for us to know,” he said. “We certainly hope it does not happen again."

“If the driver had not escaped from the car, would there have been an attack here?” asked Kelly.

Nightly News

Police scoured a landfill in New Bedford, Mass., on Friday, looking for clues in the bombings at last week's Boston Marathon.